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A quantity surveyor (QS) is a professional working within the construction industry concerned with building costs.
The profession is one that provides a qualification gained following formal education, specific training and experience that provides a general set of skills that are then applied to a diverse variety of problems. Predominantly these relate to costs and contracts on construction projects.
There are around 75,000 professional QSs working in the UK.
In the United States, QSs are called estimators.
The profession developed during the 19th century from the earlier "measurer", a specialist tradesman (often a guild member), who prepared standardised schedules for a building project in which all of the construction materials, labour activities and the like were quantified, and against which competing builders could submit priced tenders. Because all tenders were based on the same schedule of information, they could be easily compared so as to identify the best one. As a profession quantity surveying emerged around the 1820s with one of the earliest QSs being Sir Henry Arthur Hunt who was involved in work on the Houses of Parliament. After the fire in 1834 that destroyed the old Palace of Westminister Henry Hunt came up with an estimate cost of £724,984 (changes by Parliament put it up to £1.5m).
The professional institution with which most English-speaking quantity surveyors are affiliated is the UK-based Royal Institution of Chartered Surveyors (RICS). In Australia, the Australian Institute of Quantity Surveyors (AIQS) has over 4300 members, both domestically and overseas and the New Zealand Institute of Quantity Surveyors (NZIQS) a further 1300. Others are the Chartered Institute of Building (CIOB) and Chartered Institution of Civil Engineering Surveyors (CInstCES). Those who are qualified members of these organisations are entitled to use the term "Chartered Quantity Surveyor" or simply "Chartered Surveyor".